<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">
        <input type="text" v-model="txt">
        <br>
        <p id="p1">{{ txt }}</p>
        <p id="p2">{{ txt }}</p>
        <p id="p3">{{ txt }}</p>
    </div>
    <script src="../lib/vue.js"></script>
    <script>
        let vm = new Vue({
            el:"#app",
            data:{
                txt:""
            }
        })
    </script>
</body>
</html>